1. Field of the Invention
The invention relates to a winding device for recording media in tape form, in particular magnetic tapes, having at least one tape roll element, which can be rotatably driven in order to wind the tape up, the tape being pressed against the roll at the point where the tape is being wound up onto the roll by a pinch roller connected to a movable guide arm and having a flexible bearing surface.
2. Description of the Related Art
The prior art discloses systems for producing tape strips in which a continuous film web is cut longitudinally into individual film strips. This takes place with the aid of a row of fixed cutting knives which are arranged perpendicularly to the web running direction, are at equal intervals from one another and project into the web with their cutting edges directed against the web movement. The finished film strips are then wound up individually on reels or flangeless hubs on a take-up unit. In this case, the individual take-up units may be arranged in a row one behind the other or next to the other in the running direction of the film strips or, if there is quite a large number of film strips to be wound up, a plurality of rows of take-up units may also be arranged at levels one above the other.
Such systems are disclosed, for example, by German Laid-Open Application DOS 3,908,451 or by European Patent 0,297,609.
When winding up film strips, it is very important for a satisfactory appearance of the tape roll to be achieved, without overhanging turns of tape. This is achieved, for example, by German Laid-Open Application 3,818,113 in that, when producing a tape roll, a magnetic field generating device acts in a predetermined direction to attract the magnetic tape. In the said German application, further winding apparatuses are described, in which a circulating highly flexible endless belt presses the magnetic tape to be wound up against the roll in order in this way to wind the tape up neatly and firmly.
Furthermore, a winding device is known such as that represented in FIG. 1. The incoming tape strip (1) runs over a guide roller (3) having lateral rims and then over a roller (5) which has a flexible surface and presses the tape against the tape roll (7) to be wound up. Tape guide (3) and flexible roller (5) are seated on the end of a movable guide arm (2). A disadvantage of this winding apparatus is that the guide arm cannot follow rapid vertical deflections of the tape roll owing to its mass and its moment of inertia. These vertical deflections are caused by a poor centering of the hubs on the hub mounting of the winding apparatus as well as by deviations of the hub or of the tape roll from the ideal circular shape, which can occur as a result of the tape roll being compressed unevenly over its circumference when being wound under high pressure. In the case of such an arrangement, it has been observed that the vertical deflections of the guide arm described have a poor winding profile as a consequence.
A winding profile which in itself is very smooth is achieved by the winding apparatus represented in FIG. 2, as sold for example by the company Dusenberry. In this case, the incoming tape strip is wound up onto the tape roll (7) via a tape-guiding roller (8) having lateral rims (9), which guide the outer turns of said tape roll. The spacing of the lateral rims (9) from each other is only slightly greater than the width of the tape strip (1). Nevertheless, shiny and scraped places, which spoil the visual impression of the winding profile, occur on the side surfaces of the tape roll. Moreover, at high winding speeds, the winding roller tends to lift slightly off the tape roll, owing to the vertical deflection of the tape roll, as a result of which the tape can veer somewhat sideways. Upon the next-following revolution of the tape roll, the protruding tape is then damaged by the lateral rims (9) of the guide roller (8).
Cutting machines, loaders and winders contain numerous rotatable rollers, provided with lateral flanges, for deflecting the strips. Said rollers can consist of plastics material or of metal. The following problems can occur in the deflection of the magnetic tape strips on these deflecting rollers:
When the magnetic tape is cut into strips, waste (fibers, dust etc.) can be caused at the edges and damage the surface of the magnetic tape if it settles on the rollers or adheres to the magnetic tape, and thus can give rise to signal noise, known as dropouts. PA1 In the case of prolonged use of the abovementioned machines, the rotatable deflecting rollers can jam, so that the magnetic tape drags or rubs over the surface of the rollers and is thereby damaged. PA1 In the case of high running speeds, the rollers do not rotate at the tape speed, particularly in the case of a small angle of wrap, so that friction occurs on the rims. PA1 The running surface of the deflecting rollers can be damaged in the case of a prolonged service life. PA1 The edges of the magnetic tape strips can be damaged by the flanges. PA1 FIGS. 1-2 represent winding devices according to the prior art, PA1 FIGS. 3-4 represent two preferred embodiments of winding devices according to the invention, PA1 FIG. 5 represents a plan view of a deflecting roller for a winding device according to the invention, and PA1 FIG. 6 represents a cross section of the deflecting roller according to FIG. 5.
An improved roller in which the running surface is hardcoated, channel-like incisions being located between the flanges and the running surface, is disclosed by DE-U 8,811,603.
Furthermore, non-rotatable deflecting elements have been disclosed for the abovementioned purposes, to the running surface of which compressed air is applied from inside in order to avoid scratching of the film strips and in order in this way to guide the strips on an air cushion. It has been observed in this case that the lateral, likewise fixed flanges can damage the tape edges, in particular in the case of a high transport speed. Owing to the loading of the rim disks by the tape, they grind in, which can lead to damage to the tape edges.